Effect of aging of marine clay and its duplication by high temperature consolidation

By comparing the behavior of undisturbed clay samples with that of remolded samples, the effect of aging on the mechanical properties of marine clays was discussed. The compression index Cc and the secondary compression index Cα of natural aged clays show peak values when the consolidation pressure is slightly larger than the consolidation yield stress. The compression index ratio rc, which is newly introduced in this study, is considered to be a useful index to represent the aging effect of natural clays. The values of rc of Japanese alluvial clays range from 1.0 to 3.0 and they are smaller than those of East Canadian clays which are well-known as an aged clay. By consolidating clay slurry at a high temperature and cooling it after the completion of consolidation, remolded clay samples, whose mechanical properties are similar to those of lightly aged clay, can be produced in laboratory. The main cause of the effect of the high temperature consolidation seems to be the acceleration of cementation action. This procedure is useful to simulate the behavior of natural clay using laboratory tests of the remolded clays.